PROJECT SUMMARY Behavioral and emotional symptoms are prevalent, often persist for years after traumatic brain injury (TBI), and negatively affect health, psychosocial functioning, and quality of life. Assessing these symptoms over time presents unique challenges after TBI, as many current assessment tools measure individual aspects of behavior, requiring a larger battery of tools to provide a more comprehensive assessment. These instruments also often rely on clinical observation or report from a caregiver or family member, which is not often feasible for community-based symptom monitoring. Since behavior manifests in response to environmental cues, assessing behavior in real-world environments over-time, as can be done using an Ecological Momentary Assessment (EMA) approach, is critical. Current behavioral assessment tools are not designed for EMA. Thus, there is a critical need to develop valid behavioral assessment tools for monitoring behavioral/emotional symptoms as individuals with TBI reintegrate into the community. We present a theoretical framework upon which the Behavioral Assessment Screening Tool (BAST) is based and data from our BAST development study. We also present data from our pilot work examining EMA delivered via a mobile health (mHealth) system, which informed development of the BASTmHealth, which we will be assessing in the proposed project. We provide evidence that our team has the requisite skills and experience to successfully conduct the research proposed. The long-term goal of this project is to develop effective mHealth tools for monitoring behavioral symptoms for the purpose of informing interventions for individuals with TBI living in the community. We will use established methodologies for psychometric development and validation to achieve our immediate objective of validating the BAST/BASTmHealth. At the end of this project, we will have validated the BAST ? a new, comprehensive behavioral assessment tool ? for use in both research and clinical practice, and developed the BASTmHealth, a mobile health version of the BAST for EMA or long-term monitoring via a smartphone application. These data will lead directly to an R01 application to validate and field test the BASTmHealth and to assess its sensitivity to change in the context of behavioral intervention. The BAST/BASTmHealth will enable more economical and efficient monitoring of behavioral symptoms after TBI in the context of both clinical practice and future clinical trials examining behavior and emotion after TBI.